Many machines include at least one mechanism having a shaft rotatably mounted in a housing. Such a shaft typically supports one or more rotatable members thereon. In a transmission, a shaft may rotatably support one or more gears in axial alignment.
As will be appreciated, relative rotation between parts or members of a mechanism can result in friction and heat. Friction and heat are two undesirable consequences which can lead to wear of the parts and, eventually destruction of the mechanism. Bushings and/or bearings are commonly used throughout a machine to reduce friction between relatively rotating members of a mechanism. A lubricating fluid is typically delivered to the rotating members to further reduce friction and heat.
Various lubrication systems for delivering fluid through a machine and to the rotating members are known. Some lubrication systems include interconnected tubing and the like for delivering fluid from one location to another. Other lubrication systems have an axially extending fluid passage defined by a shaft for directing fluid from one location to another.
Those lubrication systems which use an axially extending fluid passage in a shaft for delivering fluid between locations typically have an open end of the fluid passage arranged in a fluid receiving chamber. Fluid pressure is created in the chamber resulting from fluid directed thereto. The pressure in the chamber causes fluid to be delivered through the fluid passage in the shaft.
Depending on the design of the particular machine, it is not always possible to accommodate the open-end of a fluid passage defined by a shaft within a fluid receiving chamber. Some machine designs require two shafts to be arranged in an end-to-end relationship. Where the terminal end of the shaft having the axial fluid passage is not accommodated within a fluid receiving chamber, the open ended passage is normally positioned proximate to a fluid supply conduit defined by a machine housing to establish a fluid connection therebetween.
Effective lubrication can be complicated by bearings used to reduce friction between the rotating shaft and the housing, which are typically arranged at the ends of the shaft. These bearings increase the radial spacing between the fluid passage defined by the shaft and an open-end of the fluid conduit in the housing. As will be appreciated, the efficiency of the fluid connection between the open-ended fluid passage in the shaft and the fluid conduit is reduced as a function of the radial distance separating the fluid passage and the fluid conduit. Moreover, most of the fluid passing from the fluid conduit in the housing passes through the bearings thereby reducing the fluid flow to the axial passage in the shaft.